[1972scoutII]

I wanted to come back and finish this thread for two reasons

1. I know it troubles me when I follow a thread that ends when no solution when I have the same problem

2. For those that wanted to lock this thread for now other reason then they had nothing to add

So here was my solution and my un-scientific reasoning

The shortest fan clutch that will mount to a early Chevy waterpump is out of Jaguar

Part numbers

Napa part # TEM261306

Hayden part #2765

AutoZone part number is 922765.

Torqflo / Fan Clutch 922765

The downside of this fan clutch is that is does not come in heavy duty meaning that is does not like a fan pitch of over 2.5 inches

So as not to overload the clutch I got a Mopar 409740 fan clutch 2.25 of pitch which was good enough to cool their 442 with AC its 19"

No fan shroud so far bit I am building one out of fiberglass

http://www.crankshaftcoalition.com/w...***_fan_shroud

Now it stays at 180 all day in 90 degree temps


Based on my testing what I have determined is that it wasnt that the Contour fan lacked in cfm it was was the fact that I have a lifted truck, and packed engine bay.

the most common thoughts is that over 30-40 mph you dont need a fan. and that is true if the air want to travel through the radiator

What the mech fan does is create some space for the air to come through at any that speed,

Your results may very

Hope I helped someone and please pm with any questions I would love to help

[cobalt327]

Is the "Mopar 409740 fan clutch" a fan only, or both a fan and clutch? I think you meant to say "...good enough to cool their 440".

I never knew that "heavy duty" when referring to a fan clutch meant a certain fan blade pitch. I'm curious, where did that info come from? I'd like to read it w/the possibility of adding the info to the Crankshaft Coalition Wiki.

Thanks for the follow up and glad you got it cooled down where you want it.

[stroker_SS]

I followed this thread start to end, and was relieved to see you come up with a solution and that you posted it as well. Good job, love scouts btw take good care of her.

[75gmck25]

This link from Hayden has info about the fan pitch used with various thermal clutches.

I think that a deeper pitch on the fan puts more load and heat on the fan clutch. The HD clutch has about double the surface area to dissipate the heat, while the severe duty clutch has six times as much surface area as the standard duty clutch.

Bruce

[1972scoutII]

The difference between heavy duty and standard is 2 things

1) The amount of pitch the clutch can handle and dissepate through the cooling fins

2) The max % of engine speed the fan clutch will turn,
Standard duty is 50-60%
Heavy duty is 80 -90%

I have seen higher pitch fans used with this clutch (A body guys) and it works, I just dont know how much it reduces the life of the clutch